1. Field of the Invention
The present invention relates to a force structure for a printing head of a printer such as a manually operable (sweeping type) handy printer.
2. Description of the Related Art
In general, a head transfer mode printer employing a line type thermal head has been equipped with a personal wordprocessor or a compact printer. In case that the thermal head having a width of, for instance, 40 millimeters is employed in such a compact handy printer, head force of several kilograms is required so as to transfer a heat transfer ink onto a recording surface of paper to be printed. Under these conditions, in a printer of, e.g., a personal wordprocessor where a thermal head is automatically pressed against a recording paper wound on a platen in order to perform a printing operation, a predetermined printing force can be set to the printing head.
However, there is such a problem in a manually sweeping type printer that the printer body must be pressed against the recording plane. This is the reason why the force is required for the printing operation. That is, generally speaking, a typical weight of the manually sweeping type printer is about 1 kg, which is lower than the printing force to be applied by the thermal head to the ink ribbon while heat-transferring the ink layer to the recording paper. As a consequence, the operation for continuously pressing the printer body against the recording paper at force higher than a predetermined value while moving the printer body, will cause a printer operator pain. When the lower force is given to the printer body, a poor printing quality is achieved. Even if too much force is applied to the printer body, various other problems may be caused.
As one problem, there is a higher risk that the printing apparatus is inclined with respect to the moving direction. Also as another problem, a fluctuation in the printer force to the recording paper may be produced, so that the driving operation of the ink ribbon interposed between the thermal head and recording paper is disturbed. In the normal trouble case, the ink ribbon is jammed on the thermal head, interrupting the printing operation. Furthermore, the need to apply the higher force against the recording paper causes the excess mechanical strength of the printing apparatus, and therefore the higher cost.